German patent publication DE-A1-36 35 958 discloses a ventilated filter cigarette with a triple filter in which the first core component adjoining the tobacco strand is a plastics film, made for example from polyethylene, which is corrugated in longitudinal direction. In this way, longitudinal ducts are formed which are essentially air- and smoke-impermeable in radial direction, with which a high pressure drop can be achieved with simultaneously low tar retention. Adjoining the first core component is a second core component, where appropriate with interposition of a middle chamber which features ventilation holes for the introduction of secondary air. The second core component is accordingly arranged in a mouth-side chamber and effects a small pressure drop with likewise relatively low tar retention. One disadvantage of this known cigarette, however, is that the strand-side core component is not environment-friendly, as it consists of a plastics film such as polyethylene. Another disadvantage is that made-to-measure production of this core component is technically costly.
European patent publication EP-B1-0 321 740 describes a ventilated coaxial filter cigarette with just one filter element in which the casing and the core filter the two different smoke flows flowing through them in a different way, but to a marked degree in each case.
Preferably, all of the primary smoke should be directed into carbon particles of an activated carbon filter. However, previously, it was not technically feasible to conduct all of the primary smoke directly into the carbon particles of an activated carbon filter.
In principle, the use of gas-phase-active material leads to an unwanted change in taste. Attempts have been made to limit this disadvantage, by coating the carbon particles as described in German Patent 2 527 569 or by using membranes made from vapor-permeable material, e.g. according to German Patent 2 355 493.
By means of a combination, described in detail in the copending patent application DE-A1-41 05 500, of (a) aromatization of the tobacco strand with a mixture of aromatic substances from two specific groups and (b) use of a specific adsorption agent and (c) making possible a specific ventilation and (d) combination of two filter elements, one achieves for example a gas-phase quantity which corresponds to a modern cigarette in the "ultra-light" range, of below 2 mg condensate/cigarette, while the particle-phase quantity of this cigarette was found to lie in the "light" range with about 5 to 6 mg condensate/cigarette, added to which there is, overall, a good taste without "after-taste or charcoal taste". Express reference is made in the present invention to this effect--which means a dramatic reduction in the "after-taste or charcoal taste".
Objects of the present invention include further developing the known filter cigarette, which has the taste of a so-called "strong" cigarette, in such a way that all filter cores can be manufactured in a simple, tailor-made process from environment-friendly material. The primary smoke of the cigarette according to the invention is preferably directed, because of the design, into and through the adsorption granulate particles of the chamber filter, which makes possible an optimum gas-phase adsorption.